Conventionally, a CT photographing (a computed tomographing) device in dental treatment obtains an FOV (Field Of View) which is set based on a size of a photo receiving surface and a mechanical geometry (an x-ray source, the center of rotation, and a geometrical arrangement of the photo receiving surface).
Also, a technique is known which is for obtaining a large FOV (field of view) by pasting projection images together in the case of an x-ray fluoroscopic photographing device (see Patent Literature 1).